jfs: Switch to generic xattr handlers

This is mostly the same as on other filesystems except for attribute
names with an "os2." prefix: for those, the prefix is not stored on
disk, and on-attribute names without a prefix have "os2." added.

As on several other filesystems, the underlying function for
setting/removing xattrs (__jfs_setxattr) removes attributes when the
value is NULL, so the set xattr handlers will work as expected.

Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

fs/jfs/namei.c

@@ -1537,10 +1537,10 @@ const struct inode_operations jfs_dir_inode_operations = {
 	.rmdir		= jfs_rmdir,
 	.mknod		= jfs_mknod,
 	.rename		= jfs_rename,
-	.setxattr	= jfs_setxattr,
-	.getxattr	= jfs_getxattr,
+	.setxattr	= generic_setxattr,
+	.getxattr	= generic_getxattr,
 	.listxattr	= jfs_listxattr,
-	.removexattr	= jfs_removexattr,
+	.removexattr	= generic_removexattr,
 	.setattr	= jfs_setattr,
 #ifdef CONFIG_JFS_POSIX_ACL
 	.get_acl	= jfs_get_acl,